Since midbrain dopaminergic neurons (mDANs) are selectively damaged in PD, we first modified the CdNS protocol to provide the regional identity around the midbrain (CdNS-MD) (Figure 7A) using Sonic Hedgehog (SHH) and FGF-8 (Gale and Li, 2008). The gene discussed is SHH; the disease is Menkes disease.